家蚕核多角体病毒的多角体蛋白基因

本文用AcMNPV多角体蛋白质基因的克隆DNA作探针,从BmS NPV DNASal Ⅰ酶酶解片段基因库中筛选出一个有同源顺序的克隆pBN 61。该克隆含大小为1.65 kb插入DNA片段。本文报道了该片段的Hind Ⅲ,Hpa Ⅱ和Alu Ⅰ等限制性内切核酸酶酶切图谱分析和部分DNA顺序分析结果。测得的DNA顺序中有138个碱基与已报道的BmSNPV多角体蛋白质一级结构中的46个氨基酸顺序相比较,除一个氨基酸发生变化外,其余完全相一致。克隆pBN 61可能包含完整的Bm SNPV多角体蛋白质结构基因。     

碱土金属钨铬杂多配合物的合成、表征及热稳定性研究

用直接法合成了以Cr为中心原子的碱土金属和W的三元杂多配合物,经ICP和TG曲线确定其化学式为K7[CrA(H2O)W11O39].xH2O(A=Mg2 ,Ca2 ,Sr2 和Ba2 ),采用IR,UV,XRD,XPS和183W NMR等手段对配合物结构进行了表征,确认所合成的配合物为-αKeggin结构.借助TG-DTA详细讨论了配合物的热稳定性,得出合成配合物的热稳定温度为450℃左右.     

Plasma-screening effects on positronium formation

Plasma-screening effects on positronium(Ps) formation for positron-hydrogen collisions in a Debye plasma environment is further investigated using the screening approximation model with the inclusion of the modified structure of Ps.More accurate Ps formation cross sections(n = 1, 2) are obtained for various Debye lengths from the Ps formation thresholds to 50 eV. The influence of considering modified bound-state wave functions and eigenenergies for the Ps is found to result in the reduction of the Ps formation cross sections at low energies, whereas it cannot counteract the enhancement of the Ps formation by the Debye screening.     

Dark diffusional enhancement of holographic multiplexed gratings in phenanthrenequinone doped poly（methyl methacrylate） photopolymer

In this paper, we experimentally investigate the dark diffusional enhancement of the optimized multiplexed grating in the phenanthrenequinone doped poly (methyl methacrylate) (PQ-PMMA) photopolymer. The possibility of improving the holographic characteristics of the material through the dark enhancement is demonstrated. The optimal preillumination exposure and the optimal time interval between exposures are extracted to obtain the optimized diffraction efficiency, and their values are 3.4×10³ mJ/cm² and 2 min, respectively. The dark enhancement of the multiplexed grating is presented as an effective method to improve the response region and the dynamic range and to prevent saturation of the material. The dependence of the phenanthrenequinone concentration on the increment of the refractive index modulation is quantitatively studied, which provides a significant basis for improving the homogeneity in the multiplexed gratings using a quantitative strategy. Finally, a simple experimental procedure using the dark enhancement is introduced to improve the homogeneity of the diffraction efficiency and to avoid the complex schedule exposure.     

钢丝绳在线非接触测长系统研究

钢丝绳成品长度是供货合同的重要指标,与经济效益、企业信誉息息相关。针对在线钢丝绳纹理变化特点,提出一种基于线结构光的非接触测长系统,通过比较钢丝绳在不同时刻,不同位置的线结构光投射条纹图像的相似性,间接测量绳长。对投射条纹提取、条纹相似性度量等关键算法进行了阐述。实验证明,系统解决了传统接触测长固有的打滑、磨损等问题,避免了钢绳在线速度变化、捻距误差等因素的影响,具有准确、高效、实时性强的特点。     

THE POLYHEDRIN GENE OF Bombyx mori NUCLEAR POLYHEDROSIS VIRUS

Cloned SalI fragments of Bombyx mori nuclear polyhedrosis virus (BmSNPV) DNA were screened with the polyhedrin gene of Autographa californica nuclear polyhedrosis virus as a probe. One positive clone, pBN61, with an insert of 1.65 Kb, was obtained. The Hind-Ⅲ, HpaⅡ and AluⅠ maps of the insert were constructed. Part of its nucleotide sequence has been determined. The 46 amino acid sequence, as determined from the nucleotide sequence, was compared with the reported sequence of BmSNPV polyhedrin. Only ono amino acid difference has been found. It is likely that clone pBN61 contains the whole BmSNPV polyhedrin gene.     

具有原核基因启动子活性的家蚕核多角体病毒的DNA片段

本文利用大肠杆菌启动子克隆用质粒pHE5,克隆和分离了家蚕核多角体病毒基因组的8种HindⅢ酶解DNA片段和一种SalⅠ酶解DNA片段。我们发现它们都具有指导抗四环素基因表达的启动子活性。测定了含有这些DNA片段的重组质粒的菌株抗四环素能力。其中最高的可以抗四环素至每毫升约30μg。我们分析了一个DNA片段的部分核苷酸顺序。发现它具有与原核基因启动子极相似的顺序结构。     

钆对K7[CrCa(OH2)W11O39]配合物的热扩渗及其导电性研究

杂多配合物是一类重要的无机配合物,广泛用于催化、药物、分子材料等诸多领域。杂多配合物导电性研究始于1979年,应用于氢-氧燃料电池等装置中,但随着工作温度提高,其导电性降低,很难作为固体电解质。因此,研究和开发稳定性高、导电性好的新型杂多配合物作为固体电解质,已成为该领域的研究热点。     

高效液相色谱法测定农药中间体氯代苯并噻唑

提出了以2-巯基苯并噻唑(SBT)为原料合成农药中间体2-氯代苯并噻唑(CBT)的高效液相色谱分析方法,对原料和产物分别进行了定量分析.在10.0～50.0 mg·L1范围内,峰面积与进样量呈线性关系,SBT和CBT相对标准偏差分别为1.29%,0.67%,平均加标回收率分别在88.9%～104.0%,88.0%～106.0%之间,检出限分别为0.01,0.005 mg·L-1.     

DNA FRAGMENTS OF Bombyx mori NUCLEAR POLYHEDROSIS VIRUS CONTAINING THE PROMOTERS ACTIVE IN PROKARYOTES

Using a promoter probe plasmid in E. coli called pHE5, eight different HindⅢ and one SalⅠDNAfragments of Bombyx mori nuclear polyhedrosis virus, directing the expression of the tetracycline re-sistance gene, have been cloned and isolated. The tetracycline resistance levels of the strains containing therecombinant plasmids were measured. Among them, the highest level of the resistance to tetracyclinewas 30μg/ml. Part of the nucleotide sequence of a DNA fragment was determined. A sequence similarto the E. coli promoter was found.